Denethor was a proud man, tall, valiant, and more kingly than any man that had appeared in Gondor for many lives of men; and he was wise also, and far-sighted, and learned in lore.... When Denethor became Steward he proved a masterful lord, holding the rule of all things in his own hand. He said little. He listened to counsel, and then followed his own mind.

The Lord of the Rings, Appendix A, Annals of the Kings and Rulers: Gondor and the Heirs of Anárion: The Stewards

In his time the peril of Gondor steadily grew, and he awaited always the great assault of Sauron that he knew was preparing. It is said that he dared to use the palantir of the White Tower, which none since the kings had looked in, and so saw much of the mind of Sauron (who had the Stone of Ithil), but was aged prematurely by this combat, and fell into despair.

The Peoples of Middle-earth, HoME Vol 12, Part 1, Ch 7, The Heirs of Elendil: The Ruling Stewards of Gondor

After [Finduilas's] death Denethor became more grim and silent than before, and would sit long alone in his tower deep in thought, foreseeing that the assault of Mordor would come in his time. It was afterwards believed that needing knowledge, but being proud, and trusting in his own strength of will, he dared to look in the palantír of the White Tower. None of the Stewards had dared to do this, nor even the kings Eärnil and Eärnur, after the fall of Minas Ithil when the palantír of Isildur came into the hands of the Enemy; for the Stone of Minas Tirith was the palantír of Anárion, most close in accord with the one that Sauron possessed.

In this way Denethor gained his great knowledge of things that passed in his realm, and far beyond his borders, at which men marvelled; but he bought the knowledge dearly, being aged before his time by his contest with the will of Sauron.

The Lord of the Rings, Appendix A, Annals of the Kings and Rulers: Gondor and the Heirs of Anárion: The Stewards

[Beregond:] And the Lord Denethor is unlike other men: he sees far. Some say that as he sits alone in his high chamber in the Tower at night, and bends his thought this way and that, he can read somewhat of the future; and that he will at times search even the mind of the Enemy, wrestling with him. And so it is that he is old, worn before his time.

The Return of the King, LoTR Book 5, Ch 1, Minas Tirith

Denethor was a man of great strength of will, and maintained the integrity of his personality until the final blow of the (apparently) mortal wound of his only surviving son. He was proud, but this was by no means merely personal: he loved Gondor and its people, and deemed himself appointed by destiny to lead them in this desperate time.

Denethor was tainted with mere politics: hence his failure, and his mistrust of Faramir. It had become for him a prime motive to preserve the polity of Gondor, as it was, against another potentate, who had made himself stronger and was to be feared and opposed for that reason rather than because he was ruthless and wicked. Denethor despised lesser men, and one may be sure did not distinguish between orcs and the allies of Mordor. If he had survived as victor, even without use of the Ring, he would have taken a long stride towards becoming himself a tyrant, and the terms and treatment he accorded to the deluded peoples of east and south would have been cruel and vengeful. He had become a 'political' leader: sc. Gondor against the rest.

The Letters of J. R. R. Tolkien, Edited by Humphrey Carpenter, Letter 183 Notes on W. H. Auden's review of The Return of the King

[Gandalf:] 'Théoden is a kindly old man. Denethor is of another sort, proud and subtle, a man of far greater lineage and power, though he is not called a king.'

The Return of the King, LoTR Book 5, Ch 1, Minas Tirith

[Gandalf:] 'He is not as other men of this time, Pippin, and whatever be his descent from father to son, by some chance the blood of Westernesse runs nearly true in him; as it does in his other son, Faramir, and yet did not in Boromir whom he loved best. He has long sight. He can perceive, if he bends his will thither, much of what is passing in the minds of men, even of those that dwell far off. It is difficult to deceive him, and dangerous to try.'

The Return of the King, LoTR Book 5, Ch 1, Minas Tirith

Pippin had an uncomfortable feeling that most of what he had said or done was somehow known to the Lord of the City, and much was guessed of what he thought as well.

The Return of the King, LoTR Book 5, Ch 4, The Siege of Gondor

Pippin marvelled at the amount that the Lord seemed to know about a people that lived far away , though it must, he thought, be many years since Denethor himself had ridden abroad.

The Return of the King, LoTR Book 5, Ch 4, The Siege of Gondor

Pippin never forgot that hour in the great hall under the piercing eye of the Lord of Gondor, stabbed ever and anon by his shrewd questions...

The Peoples of Middle-earth, HoME Vol 12, Part 1, Ch 7, The Heirs of Elendil: The Ruling Stewards of Gondor

At the foot of the dais, upon the lowest step which was broad and deep, there was a stone chair , black and unadorned, and on it sat an old man gazing at his lap. In his hand was a white rod with a golden knob....

Pippin saw his carven face with its proud bones and skin like ivory, and the long curved nose between the dark deep eyes; and he was reminded not so much of Boromir as of Aragorn.

The Return of the King, LoTR Book 5, Ch 1, Minas Tirith

A pale smile, like a gleam of cold sun on a winter's evening, passed over the old man's face....

The Return of the King, LoTR Book 5, Ch 1, Minas Tirith

[Denethor] turned his dark eyes on Gandalf, and now Pippin saw a likeness between the two, and he felt the strain between them, almost as if he saw a line of smouldering fire, drawn from eye to eye, that might suddenly burst into flame.

Denethor looked indeed more like a great wizard than Gandalf did, more kingly, beautiful, and powerful; and older.

The Return of the King, LoTR Book 5, Ch 1, Minas Tirith

There Denethor sat in a grey gloom, like an old patient spider, Pippin thought: he did not seem to have moved since the day before.

The Return of the King, LoTR Book 5, Ch 4, The Siege of Gondor

[Denethor] stood up and cast open his long black cloak, and behold! he was clad in mail beneath, and girt with a long sword, great-hilted in a sheath of black and silver. 'Thus have I walked, and thus now for many years have I slept,' he said, 'lest with age the body should grow soft and timid.'

The Return of the King, LoTR Book 5, Ch 4, The Siege of Gondor

[His use of the palantír was believed to be the cause of] the wide knowledge of events far away possessed by Denethor, and his appearance of premature old age, first observable when he was not much above sixty years old, although he belonged to a race and family that still normally had longer lives than other men.

[Pippin:] 'the Lord of the City, Beregond, has fallen before his city is taken. He is fey and dangerous.'

The Return of the King, LoTR Book 5, Ch 4, The Siege of Gondor

[There] stood the Lord of the City, tall and fell; a light like flame was in his eyes, and he held a drawn sword.

The Return of the King, LoTR Book 5, Ch 7, The Pyre of Denethor

Denethor started as one waking from a trance, and the flame died in his eyes, and he wept; and he said: 'Do not take my son from me! He calls for me.'

The Return of the King, LoTR Book 5, Ch 7, The Pyre of Denethor

Then suddenly Denethor laughed. He stood up tall and proud again,... he had between his hands a palantír. And as he held it up, it seemed to those that looked on that the globe began to glow with an inner flame, so that the lean face of the Lord was lit as with a red fire, and it seemed cut out of hard stone, sharp with black shadows, noble, proud, and terrible. His eyes glittered.

The Return of the King, LoTR Book 5, Ch 7, The Pyre of Denethor

Then Denethor leaped upon the table, and standing there wreathed in fire and smoke he took up the staff of his stewardship that lay at his feet and broke it on his knee. Casting the pieces into the blaze he bowed and laid himself on the table, clasping the palantír with both hands upon his breast. And it was said that ever after, if any man looked in that Stone, unless he had a great strength of will to turn it to other purpose, he saw only two aged hands withering in flame.

Gandalf in grief and horror turned his face away and closed the door. For a while he stood in thought, silent upon the threshold, while those outside heard the greedy roaring of the fire within. And then Denethor gave a great cry, and afterwards spoke no more, nor was ever again seen by mortal men.

[Denethor:] '[Sauron] uses others as his weapons. So do all great lords, if they are wise, Master Halfling. Or why should I sit here in my tower and think, and watch, and wait, spending even my sons?'

The Return of the King, LoTR Book 5, Ch 4, The Siege of Gondor

[Denethor:] 'The Lord of Gondor is not to be made the tool of other men's purposes, however worthy. And to him there is no purpose higher in the world as it now stands than the good of Gondor; and the rule of Gondor, my lord, is mine and no other man's, unless the king should come again.'

The Return of the King, LoTR Book 5, Ch 1, Minas Tirith

In all debatable matters of importance domestic, or external, however, even Denethor had a Council, and at least listened to what the Lords of the Fiefs and the Captains of the Forces had to say

The Letters of J. R. R. Tolkien, Edited by Humphrey Carpenter, Letter 244 From a draft to a reader of The Lord of the Rings

[The] Lord of the City was master of his Council, and he was in no mood that day to bow to others.

The Return of the King, LoTR Book 5, Ch 4, The Siege of Gondor

Thus pride increased in Denethor together with despair, until he saw in all the deeds of that time only a single combat between the Lord of the White Tower and the Lord of the Barad-dûr, and mistrusted all others who resisted Sauron, unless they served himself alone.

The Lord of the Rings, Appendix A, Annals of the Kings and Rulers: Gondor and the Heirs of Anárion: The Stewards

'I would have things as they were in all the days of my life,' answered Denethor, 'and in the days of my longfathers before me: to be the Lord of this City in peace, and leave my chair to a son after me, who would be his own master and no wizard's pupil. But if doom denies this to me, then I will have naught: neither life diminished, nor love halved, nor honour abated.'

He had married late (2976), taking as wife Finduilas, daughter of Adrahil of Dol Amroth. She was a lady of great beauty and gentle heart, but before twelve years had passed she died. Denethor loved her, in his fashion, more dearly than any other, unless it were the elder of the sons that she bore him. But it seemed to men that she withered in the guarded city, as a flower of the seaward vales set upon a barren rock. The shadow in the east filled her with horror, and she turned her eyes ever south to the sea that she missed.

The Lord of the Rings, Appendix A, Annals of the Kings and Rulers: Gondor and the Heirs of Anárion: The Stewards

The use of the palantíri was a mental strain, especially on men of later days not trained to the task, and no doubt in addition to his anxieties this strain contributed to Denethor's "grimness." It was probably felt earlier by his wife than by others and increased her unhappiness, to the hastening of her death. [Author's note.]

Faramir the younger was like [Denethor] in looks but otherwise in mind. He read the hearts of men as shrewdly as his father, but what he read moved him sooner to pity than to scorn.... He welcomed Gandalf at such times as he came to the City, and he learned what he could from his wisdom; and in this as in many other matters he displeased his father.

The Lord of the Rings, Appendix A, Annals of the Kings and Rulers: Gondor and the Heirs of Anárion: The Stewards

'...I hope that I have not done ill?' [Faramir] looked at his father.

'Ill?' cried Denethor, and his eyes flashed suddenly. 'Why do you ask? The men were under your command. Or do you ask for my judgement on all your deeds? Your bearing is lowly in my presence, yet it is long now since you turned from your own way at my counsel. See, you have spoken skilfully, as ever; but I, have I not seen your eye fixed on Mithrandir, seeking whether you said well or too much? He has long had your heart in his keeping.

The Return of the King, LoTR Book 5, Ch 4, The Siege of Gondor

'Do you wish then,' said Faramir, 'that our places had been exchanged?'

'Yes, I wish that indeed,' said Denethor. 1 'For Boromir was loyal to me and no wizard's pupil. He would have remembered his father's need, and would not have squandered what fortune gave. He would have brought me a mighty gift.'

The Return of the King, LoTR Book 5, Ch 4, The Siege of Gondor

Gandalf it was that last spoke to Faramir ere he rode east. '... Your father loves you, Faramir, and will remember it ere the end.'

The Return of the King, LoTR Book 5, Ch 4, The Siege of Gondor

The Prince Imrahil brought Faramir to the White Tower, and he said: 'Your son has returned, lord, after great deeds,' and he told all that he had seen. But Denethor rose and looked on the face of his son and was silent. Then he bade them make a bed in the chamber and lay Faramir upon it and depart. But he himself went up alone into the secret room under the summit of the Tower; and many who looked up thither at that time saw a pale light that gleamed and flickered from the narrow windows for a while, and then flashed and went out. And when Denethor descended again he went to Faramir and sat beside him without speaking, but the face of the Lord was grey, more deathlike than his son's....

Denethor grew old before [Pippin's] eyes, as if something had snapped in his proud will, and his stern mind was overthrown. Grief maybe had wrought it, and remorse. He saw tears on that once tearless face, more unbearable than wrath.

The Return of the King, LoTR Book 5, Ch 4, The Siege of Gondor

[Denethor:] 'I sent my son forth, unthanked, unblessed, out into needless peril, and here he lies with poison in his veins. Nay, nay, whatever may now betide in war, my line too is ending, even the House of the Stewards has failed. Mean folk shall rule the last remnant of the Kings of Men, lurking in the hills until all are hounded out.'

Men came to the door crying for the Lord of the City. 'Nay, I will not come down,' he said. 'I must stay beside my son. He might still speak before the end. But that is near. Follow whom you will, even the Grey Fool, though his hope has failed. Here I stay.'

The Return of the King, LoTR Book 5, Ch 4, The Siege of Gondor

Denethor started as one waking from a trance, and the flame died in his eyes, and he wept; and he said: 'Do not take my son from me! He calls for me.'

There was dismay in the City at the departure of Thorongil, and to all men it seemed a great loss, unless it were to Denethor, the son of Ecthelion, a man now ripe for the Stewardship, to which after four years he succeeded on the death of his father.

The Lord of the Rings, Appendix A, Annals of the Kings and Rulers: Gondor and the Heirs of Anárion: The Stewards

Denethor... was ever placed second to the stranger [Thorongil] in... the esteem of his father.

The Lord of the Rings, Appendix A, Annals of the Kings and Rulers: Gondor and the Heirs of Anárion: The Stewards

Denethor... was as like to Thorongil as to one of nearest kin, and yet was ever placed second to the stranger in the hearts of men and the esteem of his father. At the time many thought that Thorongil had departed before his rival became his master, though indeed Thorongil had never himself vied with Denethor, nor held himself higher than the servant of his father.... [Later], when all was made clear, many believed that Denethor, who was subtle in mind and looked further and deeper than other men of his day, had discovered who this stranger Thorongil in truth was, and suspected that he and Mithrandir designed to supplant him.

The Lord of the Rings, Appendix A, Annals of the Kings and Rulers: Gondor and the Heirs of Anárion: The Stewards

During the end of the rule of his father, Ecthelion II, [Denethor] must have greatly desired to consult the Stone, as anxiety in Gondor increased, while his own position was weakened by the fame of "Thorongil" and the favour shown to him by his father. At least one of his motives must have been jealousy of Thorongil, and hostility to Gandalf, to whom, during the ascendancy of Thorongil, his father paid much attention; Denethor desired to surpass these "usurpers" in knowledge and information, and also if possible to keep an eye on them when they were elsewhere.

Unfinished Tales, Part 4, Ch 3, The Palantíri

[Denethor] 'With the left hand thou wouldst use me for a little while as a shield against Mordor, and with the right bring up this Ranger of the North to supplant me.

'But I say to thee, Gandalf Mithrandir, I will not be thy tool! I am Steward of the House of Anárion. I will not step down to be the dotard chamberlain of an upstart. Even were his claim proved to me, still he comes but of the line of Isildur. I will not bow to such a one, last of a ragged house long bereft of lordship and dignity.'

[Gandalf:] In former days the members of my order had been well received there, but Saruman most of all. Often he had been for long the guest of the Lords of the City. Less welcome did the Lord Denethor show me then than of old, and grudgingly he permitted me to search among his hoarded scrolls and books.

The Fellowship of the Ring, LoTR Book 2, Ch 2, The Council of Elrond

Undoubtedly Gandalf's haste to reach Minas Tirith... was quickened by his sudden fear that Denethor also had made use of a palantír, the Anor-stone, and his desire to judge what effect this had had on him... Gandalf's dealings with Denethor on arrival in Minas Tirith, and in the following days, and all things that they are reported to have said to one another, must be viewed in the light of this doubt in Gandalf's mind.

Unfinished Tales, Part 4, Ch 3, The Palantíri

Thorongil often warned Ecthelion not to put trust in Saruman the White in Isengard, but to welcome rather Gandalf the Grey. But there was little love between Denethor and Gandalf; and after the days of Ecthelion there was less welcome for the Grey Pilgrim in Minas Tirith. Therefore later, when all was made clear, many believed that Denethor, who was subtle in mind and looked further and deeper than other men of his day, had discovered who this stranger Thorongil in truth was, and suspected that he and Mithrandir designed to supplant him.

The Lord of the Rings, Appendix A, Annals of the Kings and Rulers: Gondor and the Heirs of Anárion: The Stewards

The face of Denethor set hard and cold. 'You found Boromir less apt to your hand, did you not?' he said softly. 'But I who was his father say that he would have brought it to me.'

The Return of the King, LoTR Book 5, Ch 4, The Siege of Gondor

For a moment the eyes of Denethor glowed again as he faced Gandalf, and Pippin felt once more the strain between their wills; but now almost it seemed as if their glances were like blades from eye to eye, flickering as they fenced. Pippin trembled fearing some dreadful stroke. But suddenly Denethor relaxed and grew cold again. He shrugged his shoulders.

'If I had! If you had!' he said. 'Such words and ifs are vain.... In what is left, let all who fight the Enemy in their fashion be at one, and keep hope while they may, and after hope still the hardihood to die free.'

Denethor II... was... more learned in lore than any Steward for many generations.

The Peoples of Middle-earth, HoME Vol 12, Part 1, Ch 7, The Heirs of Elendil: The Ruling Stewards of Gondor

[Boromir:] Denethor, Lord of Minas Tirith, wise in the lore of Gondor.

The Fellowship of the Ring, LoTR Book 2, Ch 2, The Council of Elrond

[Gandalf quoting Denethor:] "[Unless] you have more skill even than Saruman, who has studied here long, you will find naught that is not well known to me, who am master of the lore of this City."

The Fellowship of the Ring, LoTR Book 2, Ch 2, The Council of Elrond

Quite apart from the palantíri, Denethor was a man of great mental powers, and a quick reader of thoughts behind faces and words,...

Unfinished Tales, Part 4, Ch 3, The Palantíri: Notes, Note 8

Denethor could, after he had acquired the skill, learn much of distant events by the use of the Anor-stone alone, and even after Sauron became aware of his operations he could still do so, as long as he retained the strength to control his Stone to his own purposes, in spite of Sauron's attempt to "wrench" the Anor-stone always towards himself....

Probably he did not at first look towards Mordor, but was content with such "far views" as the Stone would afford; hence his surprising knowledge of events far off.

He wedded late (for his time) in 2976 Finduilas daughter of Prince Adrahil of Dol Amroth, a noble house of southern Gondor of Númenórean blood, reputed also to have Elven-blood from ancient days.... His elder son Boromir (2978) was slain by orcs near Rauros in 3019. His younger son Faramir (2983) became the last Ruling Steward. His wife Finduilas died untimely in 2987.

The Peoples of Middle-earth, HoME Vol 12, Part 1, Ch 7, The Heirs of Elendil: The Ruling Stewards of Gondor

Denethor succeeded to the Stewardship in 2984, being then fifty-four years old: a masterful man, both wise and learned beyond the measure of those days, and strong-willed, confident in his own powers, and dauntless. His "grimness" was first observable to others after his wife Finduilas died in 2988, but it seems fairly plain that he had at once turned to the Stone as soon as he came to power, having long studied the matter of the palantíri and the traditions regarding them and their use preserved in the special archives of the Stewards, available beside the Ruling Steward only to his heir.

Unfinished Tales, Part 4, Ch 3, The Palantíri

[Confrontation] with Sauron almost certainly did not occur for many years, and was probably never originally contemplated by Denethor....

In the case of Denethor, the Steward was strengthened, even against Sauron himself, by the fact the Stones were far more amenable to legitimate users: most of all to true "Heirs of Elendil" (as Aragorn), but also to one with inherited authority (as Denethor), as compared to Saruman, or Sauron....

Denethor remained steadfast in his rejection of Sauron, but was made to believe that his victory was inevitable, and so fell into despair.... Sauron failed to dominate him and could only influence him by deceits.

Unfinished Tales, Part 4, Ch 3, The Palantíri

He must have guessed that the Ithil-stone was in evil hands, and risked contact with it, trusting his strength. His trust was not entirely unjustified. Whether he ever thus made contact with the Orthanc-stone and Saruman is not told; probably he did, and did so with profit to himself.

[Boromir:] [My] brother, seeing how desperate was our need, was eager to heed the dream and seek for Imladris; but since the way was full of doubt and danger, I took the journey upon myself. Loth was my father to give me leave....

Undoubtedly Gandalf's haste to reach Minas Tirith, in addition to the urgency of the time and the imminence of war, was quickened by his sudden fear that Denethor also had made use of a palantír, the Anor-stone, and his desire to judge what effect this had had on him: whether in the crucial test of desperate war it would not prove that he (like Saruman) was no longer to be trusted and might surrender to Mordor.

Unfinished Tales, Part 4, Ch 3, The Palantíri

Denethor was evidently aware of Gandalf's guesses and suspicions, and at once both angered and sardonically amused by them.... [He] may well also have actually seen in the Anor-stone visions of events in Rohan and Isengard. [Author's note.]

There are two alternative etymologies for the name Denethor, one a Telerin or Nandorin derivation found in The Lost Road and Other Writings, HoME Vol 5, and the other from The War of the Jewels, HoME Vol 11:

In Lhammas A the name Denethor is written over another name, very probably Denilos; in AV 1 Denilos > Denithor ( 1F. 271), in AV 2 Denithor > Denethor (note 5). In this connection there are some interesting pencilled alterations and additions in Lhammas A that were not taken up into B (or not made to it: it is not clear when these annotations were made):

Lenwë is the form in which his name was remembered in Noldorin histories. His name was probably *Denwego, Nandorin Denweg. His son was the Nandorin chieftain Denethor. These names probably meant 'lithe-and-active' and 'lithe-and-lank', from *dene- 'thin and strong, pliant, lithe', and *thara- 'tall (or long) and slender'.

The War of the Jewels, HoME Vol 11, Part 4, Quendi and Eldar: Author's Notes to Quendi and Eldar, Note 17

1Perhaps partly as a result of the way elements of this exchange are used in the movie, Denethor is sometimes considered to have actively wanted Faramir dead, and to have told him so plainly. In fact, it appears from notes made by Tolkien during the composition of The Lord of the Rings that the author intended Denethor's motivations and actions to be somewhat different:

[On] a slip of paper he wrote a brief statement of how, and why, the existing portrayal of Denethor's relations with Faramir must be changed:

The early conversation of Faramir and his father and motives must be altered. Denethor must be harsh. He must say he did wish Boromir had been at Henneth Annûn — for he would have been loyal to his father and brought him the Ring. (Gandalf may correct this.) Faramir grieved but patient. Then Denethor must be all for holding Osgiliath 'like Boromir did', while Faramir (and Gandalf?) are against it, using the arguments previously given to Denethor. At length in submission, but proudly, to please his father and show him that not only Boromir was brave [he] accepts the command at Osgiliath. Men in the City do not like it.

This will not only be truer to previous situation, but will explain Denethor's breaking up when Faramir is brought back dying, as it seems.

The first part of this passage was struck through, as far as 'Faramir grieved but patient', and the second part allowed to stand; but this was then rejected also. Finally the whole was marked with a tick, when my father at length decided that this was how it should in fact be.

The War of the Ring, HoME Vol 8, Part 3, Ch 6, The Siege of Gondor

This appears to indicate Denethor's meaning is that he merely wished Boromir had been in Ithilien, not that he wished Faramir was dead. Even a more extreme interpretation would only be that, while he would have preferred neither of his sons to die, if one of them had to die, he would rather it was Faramir than Boromir.